A method of manufacturing a magnetic recording medium includes providing a substrate that is a magnetic recording medium substrate having a disc shape, having two main surfaces, and having defined therein a center hole; holding the center hole of the substrate from both main surfaces with two holding members that each have a disc shape to hold the substrate and to cover at least the periphery of the center hole adjacent to the two main surfaces of the substrate; and applying resist liquid simultaneously to both main surfaces of the substrate using spin coating to form a resist layer simultaneously on both main surfaces while maintaining the periphery of the center hole immediately adjacent to the two main surfaces of the substrate resist-free as an unapplied portion. The method enables efficient formation of uniform resist layers without defects on both faces of the substrate.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method of manufacturing a magnetic recording medium, comprising the steps of: providing a substrate that is a magnetic recording medium substrate having a disc shape, having two main surfaces, and having defined therein a center hole; supporting the center hole of the substrate from both main surfaces with two holding members so as to hold the substrate in a vertical plane and to cover at least the periphery of the center hole adjacent to the two main surfaces of the substrate, the two holding members each having a circumferential tapered portion that tapers down toward a circumferential perimeter of the substrate, the tapered portions of the holding members being symmetrical with respect to the vertical plane; engaging one of the two holding members with a rotation shaft of a drive portion of a spin coater and detachably mating the two holding members with one another at the rotation shaft, wherein one of the holding members has a lateral protrusion and the other holding member has a depression portion that interlocks with the protrusion to prevent relative rotation of the two holding members, wherein a rotational axis of the holding members passes through the protrusion and the depression; and applying resist liquid simultaneously to both main surfaces of the substrate using spin coating to form a resist layer simultaneously on both main surfaces by directing resist liquid toward the tapered portions of each of the two holding members while maintaining the periphery of the center hole immediately adjacent to the two main surfaces of the substrate substantially resist-free, wherein the applying steps is conducted by directing the resist liquid toward locations on the tapered portions that are substantially equally distant from the rotational axis.
2. The method of manufacturing a magnetic recording medium according to claim 1 , wherein the two holding members each have at least one surface that has water-repellent properties.
3. The method of manufacturing a magnetic recording medium according to claim 2 , wherein the center hole of the substrate is closed by at least one of the two holding members.
4. The method of manufacturing a magnetic recording medium according to claim 1 , wherein the center hole of the substrate is closed by at least one of the two holding members.
5. The method of manufacturing a magnetic recording medium according to claim 1 , wherein the magnetic recording medium substrate provided includes a magnetic layer or a magnetic layer and a protective layer formed on the magnetic layer.
6. The method of manufacturing a magnetic recording medium according to claim 1 , wherein applying resist using spin coating is performed by holding the main surfaces of the substrate vertically during spinning and supplying resist liquid to the main surfaces of the substrate from a substantially horizontal direction.
7. A method of manufacturing a magnetic recording medium according to claim 1 , wherein each of the holding members includes a disc-shaped portion and has at least one surface that has water-repellent properties.
8. The method of manufacturing a magnetic recording medium according to claim 7 , wherein the center hole of the substrate is closed by at least one of the two holding members.
9. The method of manufacturing a magnetic recording medium according to claim 7 , wherein applying resist using spin costing is performed by holding the substrate vertically during spinning and supplying resist liquid by directing resist liquid toward each of the two holding members from a horizontal direction.
10. The method of manufacturing a magnetic recording medium according to claim 7 , wherein the magnetic recording medium substrate provided includes a magnetic layer or a magnetic layer and a protective layer formed on the magnetic layer.
11. A method of manufacturing a magnetic recording medium, comprising the steps of: providing a substrate that is a magnetic recording medium substrate having a disc shape, having two main surfaces, and having defined therein a center hole; supporting the center hole of the substrate from both main surfaces with two holding members that hold the substrate in a vertical plane and cover at least the periphery of the center hole adjacent to the two main surfaces of the substrate, the two holding members each having a circumferential tapered portion that tapers down toward a circumferential perimeter of the substrate and each having at least one surface that has water-repellent properties, and at least one of the two holding members closing the center hole; and engaging one of the two holding members with a rotation shaft of a drive portion of a spin coater and detachably mating the two holding members with one another at the rotation shaft, wherein one of the holding members has a protrusion and the other holding member has a depression portion that interlocks with the protrusion to prevent relative rotation of the two holding members, wherein a rotational axis of the holding members passes through the protrusion and the depression; and applying resist liquid using spin coating simultaneously to both main surfaces of the substrate by spinning the substrate and by directing resist liquid toward the tapered portions of each of the two holding members from a horizontal direction to form a resist layer simultaneously on both main surfaces while maintaining the periphery of the center hole immediately adjacent to the two main surfaces of the substrate substantially resist-free, wherein the tapered portions of the holding members are symmetrical with respect to the vertical plane, and wherein the resist liquid is applied at locations on the tapered portions that are substantially the same distance from the rotation axis of the holding members.
12. The method of manufacturing a magnetic recording medium according to claim 11 , wherein the two holding members have surfaces that have water-repellent properties.
13. The method of manufacturing a magnetic recording medium according to claim 12 , wherein the two holding members are made of polytetrafluoroethylene.
14. The method of manufacturing a magnetic recording medium according to claim 11 , wherein the magnetic recording medium substrate includes a magnetic layer or a magnetic layer and a protective layer formed on the magnetic layer.
15. A method for manufacturing a magnetic recording medium, comprising the steps of: (a) providing a disk-shaped substrate that is a magnetic recording medium substrate having first and second sides and having a center hole; (b) using first and second holding members to support the substrate in a vertical plane so that the substrate is rotatable about an axis that is perpendicular to the vertical plane and that passes through the middle of the center hole of the substrate, the first holding member having a first tapered portion that is disposed adjacent the first side of the substrate and the second holding member having a second tapered portion that is disposed adjacent the second side of the substrate, the first tapered portion and the second tapered portion being symmetrical with respect to the vertical plane; and (c) applying liquid resist to the first tapered portion at a location that is a first distance from the axis about which the substrate rotates; and (d) while step (c) is being conducted, applying liquid resist to the second tapered portion at a location that is a second distance from the axis about which the substrate rotates, wherein the first distance is substantially the same as the second distance.
16. A method for manufacturing a magnetic recording medium according to claim 15 , wherein the first holding member has a depression and the second holding member has a protrusion that fits into the depression, so as to detachably interlock the holding members.
17. A method for manufacturing a magnetic recording medium according to claim 15 , wherein the first and second tapered portions have water-repellent properties.
18. A method for manufacturing a magnetic recording medium according to claim 17 , wherein the first and second holding members are made of polytetrafluoroethylene.
19. A method for manufacturing a magnetic recording medium according to claim 15 , wherein the first and second holding members have outer peripheries that are circular and that have a common diameter, and wherein the center hole of the substrate is circular and has a diameter that is smaller than the common diameter of the holding members, so that the holding members shield the first and second sides of the substrate from the resist liquid at annular regions of the first and second sides adjacent the hole in the substrate.
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June 22, 2010
June 30, 2015
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